The sound level in a room may be reduced by the use of acoustically absorbing tiles, also called acoustic tiles. Acoustic tiles are typically arranged in a grid system covering the ceiling of the room. In order to illuminate the room from the ceiling, lighting devices may for example be arranged on the outside of the acoustic tiles (i.e. on the side of the tiles facing the room), between the acoustic tiles in the grid or as dedicated lighting tiles replacing some of the acoustic tiles in the grid. Since lighting devices typically absorb less sound than acoustic tiles of similar dimensions, their presence in the ceiling may adversely affect the acoustic properties of the ceiling and may thereby adversely affect the sound level in the room. Therefore, a trade-off is typically made between desired acoustic properties and a desired illumination. In particular, in order to limit their impact on the overall acoustic properties of the ceiling, lighting devices often cover only small portions of the ceiling, while sound absorbing surfaces cover the major part of the ceiling. Such a design, however, causes restrictions on how the room may be illuminated.
One way to provide illumination in a grid system for acoustic tiles is to integrate light sources in the acoustic tiles. In EP 2573461 A1, an acoustical lighting assembly is disclosed comprising a substrate having acoustically absorbing properties, an open cavity having side surfaces and an opening, and solid state lighting-based components located in the cavity. The acoustical lighting assembly further comprises a rigid cover of the open cavity, the cover being transparent to at least one range of wavelengths emitted by the solid state lighting based components and arranged to be acoustically non-reflective. Thus, the light emitted by the solid state lighting-based components is extracted from the assembly through the cover and the sound can go through the cover and the cavity and be absorbed by the substrate.
However, it would be desirable to provide acoustic lighting tiles (i.e. light emitting acoustic tiles), with alternative and/or improved designs for facilitating provision of a desired illumination while maintaining a desired level of sound absorption.